1997 rcsb stock L31 longblock, Marine Intake with 28# EV6 injectors, L35 2700 stall TC,Hooker LT's 2.007 60ft
the stock TCC has two weaknesses:
- single surface (i.e. only half of a clutch when you compare it to a manual trans clutch),
- shock-uptake springs in the TCC hub may not be very strong;
aftermarket TC/TCC may address those...
but, each upshift takes only a few tenths of a second... i.e. the TCC is unlocked for a very small percentage of the time, I don't believe you will see any fuel mileage increase from keeping TCC locked during upshifts.
I have an aftermarket converter with single lockup clutch. I really only intend to lockup a little early at light throttle. Before I started experimenting i was locking up around 30-32 in 4th. Now I'm thinking about locking in 3rd and maybe delaying the upshift til later.
Locking in 3rd is fine (especially if you run in manual 3rd (for example when you're not on the freeway)).Originally Posted by spy2520
Delaying the upshift (to a higher mph) is ok... in 3rd it keeps the TCC locked longer (since the upshift is delayed), and in 4th it allows the TCC to stay locked easier (since mph is now higher due to the later upshift and so you don't need as much throttle to maintain the mph).
Seems to be the way to go. I'll play with it and hopefully get it right.
Delaying the shift works pretty well. Is it really bad for the converter clutch to stay locked during an upshift at such low throttle? Right now I have it unlocking and there is a noticeable flare because of the high stall. Again this is only for low throttle applications, to avoid getting pulled over on my way to work etc.
At low throttle the TCC staying locked is probably ok.